The proposed research is designed to explore the nature of sensory-motor integration as it applies to the influence of acoustic information processing on the regulation of vocalization. Auditory information not only plays a significant role in the ongoing control of vocalization in the mature organism, but is especially important in the development of many species-specific vocal patterns, including those of human speech. The biosonar system of the mustached bat, Pteronotus parnellii, has proven strategically advantageous for the study of audition and vocalization. In particular, this study exploits the fact that mustached bats control very precisely the frequency of their biosonar signals, based upon the frequency information present in echoes. This behavior, known as "Doppler-shift compensation", involves the production and reception of comparatively simple acoustic signals, easily mimicked for experimentation, which however contain acoustic elements similar to those used in human speech. These signals and their underlying motor patterns are stereotyped and repetitively produced, both in nature and via brain stimulation. The emphasis of this study will be to analyze the organization of cortical vocal control regions (the anterior cingulate cortex) based upon the thresholds for response to synthesized biosonar sounds and on the characteristics of electrically elicited vocalization. The influence of auditory feedback on electrically elicited vocalizations by means of appropriately presented simulated echoes will be explored. In particular, the study will examine the role of cortical regions in the fine control of frequency of emitted sounds such as occurs for Doppler-shift compensation during target oriented flight.